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Somebody selling cheap oil caps now on eBay, try them in Bijou and other tube amps...?

post #1 of 11
7/6/10 at 2:11am
Thread Starter 

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=130363228747&ssPageName=STRK:MEWNX:IT#ht_1611wt_911

 

This guy is selling 245 uF / 250 VDC motor start caps for $3.49 ea.  I bought some to try as output coupling caps in my Bijou.  I'll leave a comment after I try them, but for those of you who might be interested, this looks like a good opportunity to buy some non-electrolytic caps to try out.  Compare $3.50 each  to $$$$ for "audiophile" caps, you can see what a huge markup makers of "boutique" oil caps make.

 

These are NWL T-Series capacitors, they look to be fairly recent production so likely no PCBs.  http://www.nwl.com/contents/view/34

 

!B,8LIPg!mk~$(KGrHgoOKigEjlLm,etkBKtrM8fjOw~~_1.JPG

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post #2 of 11
7/6/10 at 12:34pm

Seems interesting, and at 5.5" you may want to get some brackets and mount them like tubes above the chassis :) I seem to recall reading somewhere that motor caps are typically good for ripple applications.

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post #3 of 11
7/6/10 at 5:28pm

didn't see any mentioning of "oil" in the auction. Maybe it's metalized film?

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post #4 of 11
7/6/10 at 8:56pm



 

Quote:
Originally Posted by AudioCats View Post

didn't see any mentioning of "oil" in the auction. Maybe it's metalized film?



That makes two of us.

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post #5 of 11
7/7/10 at 9:50am

I will be grateful if you can share your impressions once you get them. Pictures, performance, etc.

 

 

 

Quote:

Originally Posted by milosz View Post

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=130363228747&ssPageName=STRK:MEWNX:IT#ht_1611wt_911

 

This guy is selling 245 uF / 250 VDC motor start caps for $3.49 ea.  I bought some to try as output coupling caps in my Bijou.  I'll leave a comment after I try them, but for those of you who might be interested, this looks like a good opportunity to buy some non-electrolytic caps to try out.  Compare $3.50 each  to $$$$ for "audiophile" caps, you can see what a huge markup makers of "boutique" oil caps make.

 

These are NWL T-Series capacitors, they look to be fairly recent production so likely no PCBs.  http://www.nwl.com/contents/view/34

 

!B,8LIPg!mk~$(KGrHgoOKigEjlLm,etkBKtrM8fjOw~~_1.JPG

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post #6 of 11
7/8/10 at 1:35pm

Not sure they are oil, or even PIO. From the NWL website:

 

We've focused on film (Aluminum film with foil & segmented metallized film) capacitors exclusively because of their lower heat dissipation and longer life compared to other dielectric types.  NWL was among the first companies to embrace this technology, and we remain at the forefront with innovative designs and state-of-the-art manufacturing processes. 

 

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post #7 of 11
7/9/10 at 10:14am



Rule #1 on motor caps,   never use motor start caps,  you want oil motor run caps,  if you see motor start,  simply run far away they are terrible for audio!

 

 

Quote:
Originally Posted by milosz View Post

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=130363228747&ssPageName=STRK:MEWNX:IT#ht_1611wt_911

 

This guy is selling 245 uF / 250 VDC motor start caps for $3.49 ea.  I bought some to try as output coupling caps in my Bijou.  I'll leave a comment after I try them, but for those of you who might be interested, this looks like a good opportunity to buy some non-electrolytic caps to try out.  Compare $3.50 each  to $$$$ for "audiophile" caps, you can see what a huge markup makers of "boutique" oil caps make.

 

These are NWL T-Series capacitors, they look to be fairly recent production so likely no PCBs.  http://www.nwl.com/contents/view/34

 

!B,8LIPg!mk~$(KGrHgoOKigEjlLm,etkBKtrM8fjOw~~_1.JPG

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post #8 of 11
7/9/10 at 12:09pm

Hence, one critical factor for this cap is whether it a motor start cap or motor run cap. Please share your info about this.

 

 

Quote:
Originally Posted by regal View Post



Rule #1 on motor caps,   never use motor start caps,  you want oil motor run caps,  if you see motor start,  simply run far away they are terrible for audio!

 

 


 
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post #9 of 11
7/9/10 at 9:55pm

Motor start are designed to deliver the pulse to get the motor going they typically have high dielectric loss at upper frequencies.   I've never seen anyone use them in an audio signal path.

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post #10 of 11
7/17/10 at 2:28am
Thread Starter 

I haven't tried them yet. 

 

Ebay seller "thought" they might be motor start caps, but didn't really know.

 

The MFG told me they are film caps typically used in power conversion equipment, such as application in AC input filters and harmonic filters in industrial equipment such as high-powered inverters. They aren't motor-run or motor-start capacitors at all. He wouldn't tell me a list price for this specific cap because it was custom OEM design, not off the shelf stock. Thus it was not on his price sheet.   He said it would be "way more than $5.00," though.

 

He said dielectric loss on this type of cap was small.  He hadn't heard of these caps being used in audio, but he said they were just a "highly developed" form of metalized polypropylene film cap that allowed a relatively high value of capacitance in a fairly compact package, with good ability to withstand industrial conditions of heat, vibration, etc. - a such, they should be good to use anywhere a metalized polypropylene film cap was a good fit. He said that NWL had developed "High Crystalline Segmented Polypropylene" dielectric material, basically a modified form of regular polypropylene that had properties that made it possible to offer smaller capacitors of a given rating, while improving thermal characteristics.

 

But you're right, they're not OIL.  They're film.  Still, should be better than polar electrolytic.  And they're $3.50 each.....


Edited by milosz - 7/17/10 at 2:32am
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post #11 of 11
7/17/10 at 8:31am

According to milosz's description, this seems to be a promising cap. Even if it could not better other well know caps, I expect it to work OK as filter cap
 

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